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i LIBRARY OF CONGRESS. I 




SUNITED STATES OF AMERICA. 



-at/ 



NOTES 



SCREW PROPULSION: 



ITS 



EISE AND PROGRESS 



W. M. WALKER, 

COMMANDEE, U. S. N. 



NEW YORK : 

D. VAN NOSTRAND, 192 BROADWAY, 

LONDON: TRUBNER & CO. 

1861. 






s 







Entered, according to Act of Congress, in tho year 1860, by 

D. TAN NOSTRAND, 

In the Clerk's Office of the District Court for the Southern District of New York. 



44—^ o n 5 



The following Notes originally appeared in 
the "Atlantic Monthly," and were so favorably 
received, that the publisher ventures to hope 
their issue in a separate form will be acceptable 
to the general reader. 

The writer desires to acknowledge his obliga- 
tions to the valuable works of Paris, Bourne, and 
Dore. 



INTRODUCTORY. 



The earliest conception of .an auxiliary motive 
power in navigation, is contemporaneous with the 
first use of the wind ; the name of the inventor, 
"unrecorded in the patent office," is lost in the 
lapse of ages. 

The first motor was, undoubtedly, the hand; 
next followed the paddle, the scull, and the oar ; 
sails were an afterthought, introduced to play the 
secondary part of an auxiliary. 

Scarce was man in possession of this means 
of impressing the wind, and resting his weary oar, 
than, scorning longer confinement to the coast, he 
boldly ventured upon the conquest of the main. 
Under the same impulse, the tiny skiff, in which 
he hardly dared to quit the river's bank, was 
enlarged, and made fit companion of his distant 
emprise. These foot-prints of the infant steps 



b INTEODUCTOEY. 

of navigation, may all still be traced among the 
maritime tribes of the Pacific. 

From that period, sails became the chief motor, 
and the paddle and the sweep auxiliaries, which 
position they still hold to some extent, even in 
vessels of considerable burden; but as the pro- 
portions of naval architecture enlarged, these 
puny instruments were thrown aside; although the 
importance and necessity of some such auxiliary 
in the ordinary exigencies of marine life, has always 
been felt, and long been earnestly sought. 

From the first successful application of steam 
to navigation — by Fulton, in 1808 — it was sup- 
posed to be the simplest thing in the world to pro- 
vide ships with an auxiliary motor, but the result 
has shown the fallacy of this conception. 

For more than twenty years steam navigation 
has advanced with giant strides, overstepping sev- 
eral times the limits which science had assigned 
it ; but the paddle-wheel, by which the agency of 
steam has been applied, forms so bad an alliance 
with canvas, and supplies so indifferently the 
requirements of a man-of-war, that it has been 
impossible by this intermediary to render steam 
the efficient coadjutor of sails ; and it is for this 
reason that steam so speedily took rank as a 
primary motor upon the ocean ; for, in all the 
successful marine applications of steam by means 



INTRODUCTOEY. 7 

of the paddle, steam is the dominant power, and 
sails the accessory, or, almost superfluous auxiliary. 
It is the screw alone, which in some of its modifi- 
cations, offers the means of a successful and eco- 
nomical adaptation of steam to ships of war or of 
commerce — for it is susceptible of a more complete 
protection than the paddle, and an easy and advan- 
tageous combination with canvas. 



SCREW PROPULSION. 



The Screw Propeller has assumed so important 
a part in all naval enterprise, that it may not be 
without interest to trace briefly its rise and pro- 
gress to the consideration it now commands, and to 
review, in general terms, the various experiments 
by which the Screw Frigate has been brought to 
her present high state of efficiency; excelling, for 
warlike purposes, all other kinds of vessels. 

As early as 1804, John Stevens, of Hoboken, 
New Jersey, engaged in experiments to devise 
some means of driving a vessel through the water 
by applying the motive power at the stern; and 
with a Screw Propeller and a defective boiler, 
attained for short distances a speed of seven knots ; 
and it is surprising that with the genius and de- 
termination so characteristic of his race, he should 



10 EARLY EXPERIMENTS. 

have abandoned the path in which he appears to 
have so fairly entered. 

Within the last half century, numerous at- 
tempts of a similar character have been made in 
Europe and America; but although many of the 
contrivances for this purpose were exceedingly in- 
genious, and the success of some of the experiments 
sufficient, one would suppose, to excite the interest 
of the public and encourage perseverance in the 
undertaking, yet in no instance were they followed 
by any useful and practical results until the year 
1836, when both Captain Ericsson and Mr. F. P. 
Smith so fully demonstrated the speed and safety 
with which vessels could be moved by the Screw 
Propeller, as to convince everj intelligent and 
unprejudiced mind of the importance of their 
inventions, and immediately to attract the atten- 
tion of the principal naval powers of the world. 

Captain Ericsson is a native of Sweden, but 
for some years previous to 1836, he had resided in 
England, where he had become known as an en- 
gineer and mechanician of distinguished ability. 

In July, 1836, he took out a patent in England, 
for his method of propelling vessels ; and during 
that year, the results of his experiments with a 
small boat were so satisfactory, that in the follow- 
ing year he built a vessel 45 feet long, with 8 feet 
beam, and drawing 3 feet water, called the Francis 



TRIAL ON THE THAMES. 11 

B. Ogden, in compliment to the gentleman then 
Con&ul of the United States at Liverpool, who wa3 
the first person to appreciate the merits of his in- 
vention, and to encourage him in his efforts to per- 
fect it. 

This vessel was tried upon the Thames in April, 
1837, and succeeded admirably. She made 10 knots 
an hour, and towed the American ship Toronto at 
the rate of 4 J knots an hour ; and in the following 
summer Sir Charles Adam, one of the Lords of the 
Admiralty, Sir William Symonds, the Surveyor of 
the Navy, and several other scientific gentlemen 
and officers of rank, were towed by her in the 
Admiralty barge at the speed of ten miles an 
hour. 

Notwithstanding this demonstration of the 
powers of his vessel, Captain Ericsson did not suc- 
ceed in exciting the interest of any of the persons 
who witnessed the performance ; and it seems al- 
most incredible, that no one of them had the intel- 
ligence to perceive, or the magnanimity to admit, 
the importance of his invention ; but, fortunately 
for Ericsson and the reputation of our country, he 
soon after met with Captain Stockton, IT. S. Navy, 
who at once took the deepest interest in his plans. 
The result of one experiment with Ericsson's 
steamer, was sufficient to convince a man of Stock- 
ton's sagacity, of the immense advantages which the 



12 THE STOCKTON. 

new motor might confer upon the commerce and 
upon the navy of his country, and forthwith he 
ordered an iron steamer to be built and fitted with 
Ericsson's propeller. 

This vessel was named .the Stockton, and was 
launched in July, 1838, and after being thoroughly 
tested and her success demonstrated, she was sent 
under sail to the United States in April of the 
next year, and was soon after followed by Captain 
Ericsson ; when, in consequence of the representa- 
tions of Captain Stockton, the Government ordered 
the Princeton to be built under Ericsson's super- 
intendence, and to be fitted with his propeller. 

The Princeton of 673 tons was launched in 
April, 1842, and her propeller of 6 blades, of 35 
feet pitch, and of 14 feet diameter, was driven by 
a semi-cylinder engine of 250 horse power, and all 
her machinery placed below the water line. 

Her smoke stack was so arranged that the 
upper parts could be let into the lower, so as 
not to be visible above the rail; and as the an- 
thracite coal which she used evolved no smoke, 
she could not, at a short distance, be distinguished 
from a sailing ship. 

Her best speed under steam alone at sea, was 
8.6, and under sail alone, 10.1 knots. Her mean 
performance under steam and sail, 8.226 ; and, con- 
sidering the imperfect form of boiler employed, and 



THE PEINCETON. 13 

the small amount of fuel consumed, it may be 
doubted if this lias since been much excelled.* 

She worked and steered well under canvas, or 
steam alone, or under both combined; was dry 
and weatherly, but pitched heavily, and was 
rather deficient in stability. 

Taking every thing into consideration, the 
Princeton was a most successful experiment, and 
in her day the most efficient man-of-war of her 
class. 

By her construction, the Government of the 
United States had placed itself far in advance of 
all the world in the path of naval improvement, 
and it is deeply to be regretted that it did not 
avail itself of the advantage thus gained; that it 
did not immediately order the construction of other 
vessels, in which successively the few defects of the 
Princeton might have been corrected ; that it did 
not persist in that path of improvement into which 
it had fortunately been directed, instead of suffer- 
ing our great naval rivals to outstrip us in the race, 
and compel us at last to resort to them for instruc- 
tion in that science, the very rudiments of which 
they had learned from us. 

The success of the Princeton was followed by 
the general adoption in America of the screw pro- 

* For particular account of Princeton, by B. F. Isherwood, TJ. S. 
Navy, see Journal of the Franklin Institute for June, 1853. 



14 POM ONE AND AMPHION. 

peller. When Ericsson embarked from England, 
lie confided his interests to Count Rosen, who, in 
1843, placed an Ericsson propeller in the French 
Frigate Pomone, and soon afterwards the British 
Admiralty determined to place it in the Amphion. 
Not only was the performance of these vessels 
highly satisfactory, but they were the first ships in 
the navies of Europe, in which the great desidera- 
tum was secured of placing the machinery below 
the load line. Ericsson's propeller having been the 
first introduced into France, it became generally 
adopted ; but afterwards, in consequence of the ac- 
counts of Smith's Screw received from England, it 
underwent various modifications. 

Such was the result of Ericsson's labors ; it 
now remains to relate the success of Smith. The 
efforts of either had been sufficient to have secured 
to navigation the inestimable advantages of Screw 
Propulsion, but their rivalry probably hastened 
the solution of the problem. 

In May, 1836, Mr. F. P. Smith, a farmer of 
Hendon, in England, took out a patent for his 
Screw Propeller, and exhibited some experiments 
with it attached to a model boat, and in the 
following autumn built a boat of 6 tons burthen, 
of 10 horse power, and fitted with a wooden 
screw. 

This vessel was kept running upon the Thames 



THE ARCHIMEDES. 15 

for nearly a year, and her performance was so sat- 
isfactory, that Mr. Smith determined to try her 
qualities at sea; and in the course of the year 
1837, he visited in her several ports on the coast 
of England, and proved that she worked well in 
strong winds and rough water. 

These trials attracted much attention, and at 
last awakened the interest of the Admiralty, who 
requested Mr. Smith to try his propeller on a 
larger vessel, and the Archimedes of 90 horse 
power and 237 tons, built for this purpose, was 
launched in October, 1838, and made' her experi- 
mental trip in 1839. 

It was thought her performance would be 
satisfactory if she could make four or five knots 
an hour, but she made nearly ten ! In May, 
1839, she went from Gravesend to Portsmouth, 
a distance of 190 miles, and made the run in 20 
hours. 

In April, 1840, Captain Chappel, R. N., and 
Mr. Lloyd, Chief Engineer of Woolwich Dock 
Yard, were appointed by the Admiralty to try a 
series of experiments with her at Dover. The 
numerous trials made under the superintendence 
of these officers, fully proved the efficiency of the 
new propeller, and their report was entirely favor- 
able. 

The Archimedes next circumnavigated Great 



16 SCEEW GROWS IN FAVOE. 

Britain under command of Captain Chappel, visit- 
ing all the principal ports: she afterwards went 
to Oporto, Antwerp, and other places, and every- 
where excited the admiration of engineers and 
seamen. 

Up to this period, the British engineers were 
nearly unanimous in the opinion, that the use of 
the Screw involved a great loss of power, and they 
had concluded that it could not be adopted ; but 
it was impossible any longer to resist the impres- 
sions made on the public by the demonstration 
which had been given both by Smith and Ericsson ; 
and, although the engineers were still unwilling to 
admit the screw to a comparison with the paddle, 
it was evident that their first conclusions regard- 
ing it were erroneous, and thereafter it was viewed 
by them with less disdain, and spoken of more 
hopefully. One of the great objections by engi- 
neers to the use of the screw, was their inability, 
at the time of its introduction, 'to construct prop- 
erly a screw engine ; that is to say, a direct act- 
ing horizontal engine, working at a speed of from 
sixty to one hundred revolutions per minute — all 
their experience having been in paddle-wheel en- 
gines, working from ten to fifteen revolutions per 
minute. 

The peculiar mechanical details required in 
the screw engine, the necessity for accurate coun- 



FIRST SCEEW ENGINES. 17 

terbalancing, &c, were then unknown, and had to 
he learned from a long succession of expensive 
failures. In England, the first machines applied 
to the screw, were paddle-wheel engines, work- 
ing it by gearing ; there were consequently lost 
all the advantages of the reduced cost, bulk, and 
weight, of the screw engine proper, including, for 
war purposes, the important feature of its being 
placed below the water line. At first the screw had 
not only to contend with physical difficulties, but to 
straggle against nearly universal prejudice ; many, 
inventors had succumbed to these obstacles, and 
therefore too much applause cannot be bestowed 
upon those, who, unsustained by public sympathy, 
and in defiance of a prevailing skepticism, main- 
tained their faith and courage unshaken, and gal- 
lantly persisted in their efforts, until crowned with 
a world-wide success. 

Ericsson, before interesting himself with the 
screw, was, as has been seen, an engineer and 
mechanician of distinguished ability ; whereas 
Smith, in commencing his new vocation, had all 
to acquire but his first conception. Ericsson could 
rely upon the fertility of his own genius, was his 
own draughtsman, and designed his own engines; 
accommodating them to the new propeller by 
dispensing with gearing, and adapting them to 
a speed of from thirty to forty revolutions — a 

2 



18 THE BATTLE E. 

great and bold advance for an initiative step. 
Smith, on the contrary, not being an engineer, 
had to intrust the execution of his plans to others, 
whose knowledge of construction was in the rou- 
tine of paddle-wheel engines, and this accounts 
for the fact, that all the earliest British screw 
steamers were driven by gearing. 

This want of mechanical resources, on the 
part of Smith, added to the difficulties of his 
career; but his resolution and perseverance rose 
superior to all obstacles, and carried him to the 
goal in triumph. 

Briefly, then, these were the respective merits of 
Smith and Ericsson, in the introduction of Screw 
Propulsion; and it is much to their honor, that, 
throughout their career, no narrow-spirited jeal- 
ousies dimmed the lustre of a noble rivalry. 

Such was the origin of the new motor; the 
mighty engine by which armadas are marshalled 
in battle array, the burdens of commerce borne 
to distant marts, the impatient emigrant trans- 
ferred to the promised land, and by which the 
breathings of affection, the pangs of distress, 
and the sighs of love, are wafted to far-off con- 
tinents. 

In consequence of the success of the Archimedes, 
the Admiralty ordered the Rattler to be fitted 
with a screw, and it was no small satisfaction to 



FURTHER TRIALS. 19 

find that her double cylinder engines could be 
easily adapted to the new propeller. She is of 888 
tons, and 200 horse power, and was launched in 
the spring of 1843, being the first screw vessel in 
the British Navy. 

In the course of the two succeeding years, she 
was tried with a great many different screws, and 
numerous experiments were made to discover the 
length, diameter, pitch, and number of blades of 
the screw, most effective in all the various con- 
ditions of wind and sea. A screw of two blades, 
each equal to one-sixth part of a convolution, and 
of a uniform pitch, was, on the whole, found to 
be the most efficient, and this is the screw now 
adopted in most of the ships of all classes in the 
British Navy* A propeller of very different con- 
struction, which had given great results in a ship 
of the Peninsular and Oriental Steam Ship Com- 
pany, and was afterwards exhibited in the docks 
at Southampton, here claims a passing notice. 

This propeller is so constructed, as to enable 
the engineer to regulate the speed of the piston, 
for the pitch of the screw can be increased or di- 
minished at pleasure. Thus, with a fair wind, by 

* A series of experiments with the screw were made on hoard the 
Dwarf in 1845, and on hoard the Minx in 1847 and 1848, hut the re- 
sults did not materially differ from those previously ohtained. In the 
Rattler, Dwarf, and Minx, twenty-nine different propellers were tried. 



20 EATTLEE A M" D ALECTO. 

increasing the pitch, without increasing the revo- 
lutions, the full power of the engine is effectually 
exerted in driving the ship, instead of consuming 
fuel in driving the engine to no purpose ; and with 
a head wind by diminishing the pitch, the engines 
are made to do their utmost duty, and when the 
ship is under canvas only, the blades of the pro- 
peller may be placed in line with the stern-post, 
and thus offer little resistance. Another advantage 
claimed for this propeller (known as Griffith's) is 
that, in the event of breaking a blade, it may be 
readily replaced by " tipping the ship ; " which 
method merits careful consideration by engineers, 
as does especially every new propeller, which 
promises a more perfect alliance with canvas. 

To resume the narrative, the speed of the 
Eattler was afterwards tested by a trial with the 
Alecto, a paddle-wheel steamer of equal power, 
built from the same moulds ; and the result was 
so favorable that the Admiralty ordered the con- 
struction or conversion of twenty-three vessels as 
screw steamers, and thus was laid the foundation 
of their present formidable Steam Navy. 

The superiority which has been asserted for the 
Princeton, was established during the Mexican 
war, by her performance before Vera Cruz, as 
a blockading ship of unprecedented efficiency: 
which having been displayed under the admiring 



THE MINNESOTA. 21 

observation of a British squadron, more than any 
other single event, tended to confirm the Admiralty 
-in the conclusions to be drawn from the experi- 
ments just related ; and to influence them in the 
adoption of the screw as the best auxiliary of sail, 
the best mechanical motor upon the ocean. 

Thus did England, in embracing at once the 
practical demonstration of the Princeton, display 
that forecast by which she won her ascendency at 
sea, and the vigilance with which she maintains it 
whilst our own government awaited, in unbecom- 
ing hesitation, the results which England's more 
extended trials with the screw might develop. 

This cautious policy, rather than the bold and 
liberal course which the maritime genius of the 
country demands, condemned us for long years 
to inaction, until, at length the absolute necessity 
for the renewal of a portion of our naval force, 
produced the Minnesota class of Frigates; and, 
although they developed little that was absolutely 
new, they are very far from being imitations; 
but in model, capacity, equipment, and above all in 
their armament, they have challenged admiration 
throughout the world, and called from ' a distin- 
guished British Admiral in command, the significant 
declaration that, until he had seen them, he had 
never realized his ideal of a perfect man-of-war. 

A leading idea in the conception of these ships 



22 NEW VIEWS. 

was, to reduce the number of gun-decks from 
two and three to a single deck ; and consequently, 
the space in which shells could be lodged. This 
is a consideration which must, it is conceived, 
sooner or later govern in naval construction — 
although France and England, long accustomed 
to measure the power of ships by the number of 
gun-decks, may be more slow in following our lead 
in this respect, than in imitating the increased 
calibre of our ordnance. 

The new classes of steamers preparing for sea, 
of which the Hartford and Iroquois are types, 
promise to be most efficient ships, and to reflect 
much credit upon our Naval Authorities for 
their bold, yet judicious, departure, from traditions 
which had long hampered the administration of 
this important branch of the public service, — for, 
although the reflection is seldom made, it is never- 
theless true, that much of the reputation enjoyed, 
and influence exercised by the United States, is 
due to the efficiency of her navy. If these are to 
remain undiminished, then it is of the utmost 
consequence that the national ships shall always 
represent the highest advancement of nautico- 
military science. 

The efficiency of the screw having been demon- 
strated, it was seen that the next requirement for 
a war steamer was to place her machinery below 



THE ADMIRALTY. 23 

the water line ; and hence arose a demand for an 
entirely new description of engines, which it was 
clear would make a great change in all the labors 
of the engineer and machinist. Such change it 
was evident would greatly enhance the risk of 
failure, and therefore, it was determined by the 
Admiralty to ensure success in this very difficult 
task, by enlisting all the best talent of the country. 
Accordingly, for the twenty-three ships an equal 
number of screw engines were ordered ; and, as 
with the constructors, so with the engineers, each 
was required to comply with certain conditions, 
yet each was permitted to put forth his own indi- 
viduality, and each has illustrated his views of 
what was required, by a distinct plan of engine. 

The wise aud liberal action of the British 
Admiralty, which faltered at no expense, and 
made trial of every improvement in machinery 
that gave assurance of good performance, and 
promised in any way to increase the efficiency of 
the fleet, produced no less than fourteen distinct 
varieties of the screw engine. Among them all, 
Penn's horizontal trunk engine appears to be the 
favorite, and had performed so well in the Encoun- 
ter of 14 guns, the Arrogant of 46, the Imperieuse 
of 50, and the Agamemnon of 90, that two years 
ago it had been placed in about equal proportions 
of 200, 400, 600 and 800 horse-power on board of 



24 TEU^K ENGINES. 

forty ships, and many smaller vessels of the British 
Navy; it had fulfilled all the promises made for 
it, without requiring in any instance repairs. 

These engines comply with all the conditions 
reasonably demanded in the machinery of a man- 
of-war; they lie very low, and the fewness and 
accessibility of their parts, leaves scarcely any 
thing to be desired ; a lighter, more compact, or 
more simple combination, has yet to be con- 
ceived* 

In all the ships above referred to, the con 
nection of the engines is direct, and many of 
them are driven at rates varying from fifty to 
seventy-five revolutions. This point is dwelt 
upon, because it is observed that many engineers 
find difficulty in freeing themselves from early 
impressions made by long stroke engines, ex- 
press apprehensions at fifty and sixty revolu- 
tions, and stand ready to obviate the difficulty by 
gearing, which it is hoped may not henceforth 
be adopted in our national ships. Geared engines 
are much heavier than those of direct connection, 
and occupy more space, a great consideration in 
ships where room for fuel is in such demand, be- 
sides making it more difficult to place them below 

* "Its large amount of friction," is an objection often speciously 
urged to the trunk engine, although the friction diagram shows it to 
be actually less in this, than in most other engines. 



HOEIZONTAL ENGINES. 25 

the water line, a consideration which in men- 
of-war, should be regarded of paramount impor- 
tance, as the engines of a war steamer should 
be as secure from shot as her magazine. Expe- 
rience has shown that the apprehensions enter- 
tained from the quick stroke of direct engines 
were without foundation ; and, that in auxiliary 
ships, with a properly modelled propeller, there 
will be no necessity for a very high speed of 
piston. 

The form of engine generally adopted with 
great success in the later screw ships of the 
United States Navy, is the ''Horizontal direct 
action," with the connecting rod returning 
from a cross-head towards the cylinder; these 
engines make from sixty to eighty revolutions 
per minute. The steam valve is a packed 
slide, with but little lap, and the expansion 
valve is an adjustable slide working on the 
back of the steam valve. The boilers are of 
the vertical water-tube type, with the tubes 
above the furnaces, and are supplied with fresh 
water by tubular surface condensers, which, 
together with the air-pumps, are placed opposite 
the cylinders. 



26 EXPEEIMENTS WITH THE DWAKF. 

While the vessels ordered by the Admiralty 
were on the stocks, it was suggested by Mr. Lloyd, 
that the model of their after bodies was not that 
most favorable to speed; that they were too "full," 
and that a "finer run" would be preferable. 

To settle this question, the Dwarf, a vessel of 
fine run, was taken into dock, and her after 
body filled out by three separate .layers of plank- 
ing, so as to give it the form and proportions of 
the vessels then building. 

These layers of planking could be removed in 
succession, and the effects of a fuller or finer run 
upon the speed of the vessel, easily ascertained. A 
trial was then made, and the result proved the cor- 
rectness of Mr. Lloyd's opinion ; the removal of the 
different layers of planking increasing the speed 
from 3.75 to 5.75, to 9, and finally to 11 knots. 

A trial between the Rifleman and the Sharp- 
shooter, vessels of 480 tons and 200 horse-power, 
and the Minx and Teaser of 300 tons and 100 
horse-power, gave similar results ; the speed in 
each trial being 24 per cent, in favor of the finer 
run. 

Although great efficiency and economy had 
now been attained, there was still an important 
defect to be remedied, namely, the impediment to 
speed and to evolution under sail, presented by the 
dragging propeller; which was accomplished by 




(28) 



MODE OF LIFTING SCEEW, 



LIFTING THE SCREW. 29 

the invention of the "Trunk" or "Well," into 
which the propeller can be raised at pleasure ; and 
there is no longer any thing to prevent the con- 
struction of a Screw Frigate which shall be fit to 
accompany, under canvas only, a fleet of fast sailers, 
with the assurance that she may arrive at the point 
of destination in company with her consorts, having 
in reserve all her steam power. 

The mechanism by which the emersion of the 
screw is effected, is as follows : there are two stern- 
posts; between these, and connecting them with 
each other and with the keel, is a massive metallic 
frame, in which rests another frame or "chassis," 
in which the screw is suspended : near the water 
line, the deck and wales are extended to the after 
stern-post, and through an opening or trunk in this 
overhanging stern, the frame suspending the screw 
is raised by worms, working in a rack secured to 
the frame, and operated from the deck, as shown 
in the accompanying drawing ; or, by a tackle as is 
now most common. 

In the British ship Agamemnon, of 90 guns, 
the propeller is raised by a hydrostatic pump, a 
neat arrangement, but liable to get out of order. 

When it is desirable to raise the propeller, 
the blades are first placed in a vertical position, 
and the operation of lifting is performed in a few 
minutes. 



BO ADVANTAGES AND DISADVANTAGES. 

The relative advantages of the propeller fitted 
to lift, and that which is permanently fixed, have 
long been the subject of much discussion. 

For merchant steamers, having an established 
route to perform, on which the aid of steam is in 
constant demand, it is generally conceded that the 
position of the screw should be permanent. The 
construction of the ship is then less costly, while 
greater strength is preserved ; and as these vessels 
are out of port but for short intervals, should re- 
pairs be needed, they have access to the docks. 
But for men-of-war, the case is widely different. 
Having frequently to keep the sea for long periods, 
much under canvas, and often far distant from a 
dock-yard, they should be provided with the means 
of lifting the screw to repair or to clear it, or to 
be relieved from the impediment it offers to sail- 
ing and to evolution, and also from the injurious 
" shake? occasioned by a dragging propeller. 

On the other hand, the construction of a trunk 
or well, impairs the solidity of the stern, renders it 
much more vulnerable, and weakens its defences, 
while it opposes to speed the very considerable re- 
sistance of the after stern-post.* Nevertheless, no 
modern ship of the British Navy is without the 
means of raising her propeller, and the best opin- 

* Might not a metallic stern-post, combining strength, lightness, 
and little resistance, be introduced ? 



A DEAGGING PROPELLER. 31 

ion of commanders and engineers of that service, 
of longest experience in screw-ships, goes to estab- 
lish the conviction that, for men-of-war, the advan- 
tages of being able to lift the propeller, far more 
than outweigh the objections urged against lift- 
ing. In this connection we mention the fact that 
all screw ships "by the wind," have a strong ten- 
dency to gripe. Would not this be obviated by 
having a gate or slide to fill out the dead-wood 
when the screw is lifted ? 

The best illustration of the effects of a drag- 
ging propeller, was afforded on the departure 
of a Russian squadron from Cronstadt, bound 
to the Amoor, in 1857-58, consisting of three 
sloops of war barque-rigged, and three three- 
masted schooners, under the flag of Commodore 
Kouznetsoff. The vessels of each class were built 
from the same moulds, and at the time of the ex- 
periment were of the same draft and displacement. 

On clearing the land, signal was made to 
lift screws and make sail. Soon after, all the 
squadron reported the execution of the order, 
except the Voyerada sloop, which had the mis- 
fortune to break a key in the couplings, and there- 
fore could not lift her screw. Every effort was 
tried to get out the key, and meanwhile a very 
instructive example was presented to the squadron 
of the effect of a dragging propeller on the speed 



32 THE 

of the vessel. The circumstances were as follows: 
The wind, a gentle breeze, right aft, Voyerada car- 
rying all sail but main conrse, the other two 
sloops holding way with her with their topsails 
on the cap, and the schooners with their peaks 
dropped. Under these conditions, the Voyerada 
having her screw blades fixed horizontally, could 
scarcely keep her position, running 2^ and 3 
knots. The Voyerada next succeeded in getting 
her screw vertical, when, without any change in 
the wind, the speed increased to 4J knots. The 
other sloops then mastheaded their topsails, and 
the schooners peaked their gaffs. At length the 
Voyerada succeeded in lifting her screw, when 
immediately all sloops uncler the same canvas 
continued their course, making 6 to 6J knots. A 
better example of the obstruction offered by a 
dragging propeller could not have been afforded.* 

The " shake," to which reference has been made, 
is the tremulous or vibratory motion communicated 
to the after body of the ship, and particularly 
to the stern, by the revolution of the propeller, 
often opening the seams, and in old ships some- 
times starting the butts, and causing dangerous 
leaks. This movement arises from two causes, one 
inherent in the screw, the other due to its position 
in the dead-wood. 

* Russian Nautical Magazine, No. XLL, December, 1857. 



EXPEEI MENTAL CRUISE 



33 



The first cause is the difference in the pro- 
pelling efficiency of the upper and lower blades 
when in any other position than horizontal. The 
centre of pressure of the lower blade being at a 
greater depth below the surface than the centre 
of pressure of the upper blade, acts upon a medium 
of greater resistance to displacement, and the 
differential of the pressures of the two blades 
produces inevitably a vibratory motion in the 
stern of the vessel. This effect is greatly increased 
when the clearance given to the screw in the dead- 
wood is too small ; for the reduction of the hydro- 
static pressure at the stern-post, and the increase 
of it at the rudder-post, on each passage of the 
blades, must be followed by concussion. 

Therefore, if the "well," or distance between 
the posts be made sufficiently loug in proportion to 
the screw, the " shake," due to the latter cause, can 
be almost entirely obviated. 



In 1851, the British Admiralty selected three 
auxiliary screw ships, of different classes and quali- 
ties, for an experimental cruise, viz.: 



The Arrogant, 
" Dauntless, 
" Encounter. 



Guns. 



46 
24 
U 



H. Power. 



360 
580 
360 



Screw. 



Speed. Days Fuel. Sail Equipment, 



2 blades. i9kn'ts. 
« 11 « 

" JlOi " 



8 days. 
11 " 
6 " 



Ship full rig. 
" light " 
Barque. 



34 OTEEESTOG TEIALS. 

They were ordered to pass round the Azores, 
each ship holding her course, and using sail or 
steam, or both, as was deemed most advantageous. 
An officer was sent on board each ship to keep a 
record of her performance, and to note the time 
when, and position where, the coal being entirely 
consumed, the contest ended. 

In this trial, the Arrogant was found superior 
to the Dauntless, and both of them far excelled 
the Encounter ; indeed, no very different result was 
expected, the object of the trial being to ascertain 
their relative as well as positive value. 

These ships afterwards formed a part of the 
Experimental squadron, stationed at Lisbon in the 
same year, which was composed of the finest ships 
in the British Navy. 

It was believed by many officers, that a fast 
sailing Frigate in a reefed top-sail breeze, would be 
able to get away from any Screw ship ; but in a 
trial that took place between the Arethusa and the 
Encounter, and the Phaeton and Arrogant, under 
circumstances the most favorable to the sailing 
ships, it was found that the Screw ships using 
both steam and sail, had decidedly the supe- 
riority ; and that in fresh gales with one, two, 
or three reefs in the topsails, either "by the 
wind," or "going free," the Phaeton and the 
Arethusa, the fastest sail Frigates in the Navy, 



EXPERIMENTS BY THE FRENCH. 35 

were always beaten by the. Arrogant. This re- 
sult operated powerfully in removing the repug- 
nance to steam existing among all classes of seamen ; 
and the vast superiority of well-organized screw 
ships for the purposes of war, is now so apparent, 
as to render them the most important and indis- 
pensable part of every navy. 

While the British were engaged in the trials 
here related, their rivals on the opposite coast were 
not indifferent spectators. 

The French were nearly as soon in the field of 
modern Screw experiment as their neighbors, and 
did the limits of this paper permit, it would be in- 
structive as well as interesting, to trace the ingen- 
ious and persevering steps, by which they also 
approached the solution of that difficult problem, 
the construction of a Screw man-of-war. The first 
result of their efforts, La Pomone Screw Frigate, 
was shown to the world in 1844, and after careful 
inspection (in 1853), it is affirmed, such was the 
perfection of her general organization, that she 
has hardly been excelled by any of her younger 
sisters. 

The most complete course of experiments ever 
made, perhaps, with the new motor, was that car- 
ried out by MM. Bourgois and Moll of the French 
Navy, in 1847 and '48, which they verified by a 
second series in 1849. These experiments were 



36 FRENCH CONTRIBUTIONS. 

instituted to ascertain the relative efficiency of all 
varieties of the Screw Propeller, upon vessels of 
different models and dimensions, and under all the 
varying conditions of wind and sea, in order to 
determine the propeller best adapted to each par- 
ticular description of ship.* 

Brief as is, necessarily, the notice of Gallic in- 
genuity and skill, the acknowledgment must be 
made that, for the invention of the Trunk or Well 
with its attendant advantages, navigation is in- 
debted to Commander Labrousse, of the French 
Navy ; and for a novel arrangement of the Screw 
Propeller, which has not attracted all the notice 
it deserves, obligations are due to M. Allix, a dis- 
tinguished engineer of that service ; and the pro- 
peller more recently introduced by M. Mangin, 
of the same corps, if it performs all that is claimed 
for it, namely that it does away with the " Shake," 
will be of great value. 

In concluding this recognition of the contribu- 
tions by France to Screw Propulsion, it is desired 
to submit a few general observations on the 
French Navy: for, although upon every sea the 
tri-color waves over ships proudly comparing with 
those under any other flag, it is nevertheless too 

* For a most interesting and instructive memoir upon these ex- 
periments, the reader is referred to that admirahle work by Captain 
E. Paris, of the French Navy, "L'Helice Propulsive." 



NAVY OF FRANCE. 37 

commonly believed that the docks of France are 
crowded, and her navy list swollen, with hulks 
which are but the mouldering mementos of the 
vast armaments hastily created during "the Con- 
sulate and the Empire;" an illusion most hazard- 
ous to our interests abroad, and our security at 
home. 

At the period of the "coup d'etat" of 1851, 
a Committee of Inquiry, composed of the most 
experienced and intelligent officers and distin- 
guished legislators, had visited all departments 
of the navy, and made the most careful investi- 
gations into every branch of the service. Upon 
the evidence thus obtained, a report was sub- 
mitted, providing for the improvement of the 
condition of the officers and seamen, and the 
increase, renewal, and remodelling of the "ma- 
teriel ; " in fine, for the correction of ( every 
abuse, the remedy of every evil, and the develop- 
ment of all good existing in the navy. 

This report, stamped on every page with 
patriotism and intelligence, commanded, even in 
the midst of revolution, the support of all parties, 
the adhesion of every faction ; and has since, through 
all changes in the ministry of the marine, formed 
the basis of the action of that department. 

Under these auspices, France has in the last 
seven years, organized the means of promptly put- 



38 SCKEW FLEETS. 

ting to sea a numerous fleet, composed of 
the most modern . and most powerful steamers, 
manned by efficient crews, commanded by skilful 
officers ; and now worthily maintains a position as 
a naval power second only to that of Great 
Britain. 

At this moment, whilst the British fleet in- 
cludes but 36 screw line-of-battle* ships, mounting 
3,400 guns, and propelled by 19,759 horse-power, 
that of France may boast of 40 such ships, mount- 
ing 3,700 guns, propelled by 27,500 horse-power; 
and while England has but 38 Screw Frigates, 
France has 42. 

In thus briefly summing up the forces of our 
ocean rivals, we cannot avoid making some reflec- 
tions suggested by the impreparation of this coun- 
try to meet 'any sudden burst of hostility. This 
not only hazards national humiliation, but para- 
lyzes our diplomacy ; since it deprives us of that 
influence among the nations, which otherwise — from 
the breadth of our territory, the value of our pro- 
ducts, the activity of our industry, the importance 
of our commerce, and the extent of our maritime 
resources — we of right should hold. 

No country is more interested than the United 
States in the maintenance of peace, yet even on 
the principle of economy, may be argued a degree 
of preparation for war ; for that calamity may best 



SOME KEFLECTIONS. 39 

be averted by taking from foreign powers the 
temptation to interfere with us : all history show- 
ing that the justice and friendship of military 
states are but slender guaranties for the peace of a 
nation unprepared for attack. 

It is vain to talk of husbanding financial 
resources for war, without other preparation. 
When once embarked in hostilities, and in a 
position to maintain our ground, large finances 
judiciously used, will ultimately command success ; 
but no accumulation of funds can provide a timely 
remedy for that weakness which cannot resist the 
first blow ! 

The national safety should be no longer left to 
chance, but established on a basis of certainty, A 
navy cannot be manufactured, nor a fortress built, to 
meet an emergency, but should be kept ready made. 



In considering the auxiliary Screw Frigate under 
the views already expressed, and in determining the 
canvas with which she should be supplied, it will be 
well to refer as the best guide to the fastest sail 
ships— the class which presents the greatest simi- 
larity in form to that demanded in screw ships. In 
these ships, the great length of deck offers every 
facility for the most advantageous spread of canvas, 



40 THE SCREW FRIGATE. 

consequently the centre of effort may be kept low, 
and the requisite power and stability combined. 

Intimately connected with her sail power, 
is another branch of the equipment of a screw 
ship which requires the most earnest, patient, and 
intelligent consideration. Prepared to endure all 
the " wear and tear " of a sailing ship, she should 
at the same time be ready for -transition into a 
steam ship; namely, when for any urgent service 
her best powers of steaming are required, she 
should be able to divest herself speedily of yards 
and topmasts, and the special service completed, 
resume again all her perfection as a sailing ship. 

It would be out of place here to enter into 
details of equipments ; in naval affairs nothing is 
improvised, and a satisfactory conclusion upon 
these points can only be arrived at through long 
experiment, and perhaps frequent disappointment. 
Yet it is not doubted that the same ship may 
exhibit a handy and efficient rig, develop a high 
velocity under canvas, and without great power, a 
sufficient speed under steam. 

In our navy, away from our own coast, sail 
must of necessity be the rule, and steam the reserve 
or special power ; and without abandonment of 
our anti-colonial policy — with the depots of our 
rivals upon every sea, yet not a ton of coal upon 
which we can rely — we should not dare to send 



CONSTRUCTORS ENGINEERS. 41 

abroad a single ship, which, whenever she gets 
up her anchor, must needs also get up her steam. 

Fortunately, in the creation of a steam fleet, 
the United States will not have to encounter 
tedious and costly experiments, nor to incur the 
risk of failure.* The best form of hull, model of 
propeller, and plan of engine, are already so well 
established, that it is not easy to fall into error ; 
that which is most to be guarded against is, the 
popular demand, the prevailing mania for high 
speed, for which single advantage there is such a 
proneness to sacrifice every other warlike quality. 
That measure of speed or power which will enable 
a ship to stem the currents of rivers, to enter or 
leave a port in the face of a moderate gale, or 
to meet the dangers of a lee-shore, should, it is 
conceived by many, be sufficient ; and for these 
exigencies, a ship which, with four months 7 supplies 
on board, can in calm weather and smooth water 
make 9 to 10 knots under steam, has ample power. 
This moderate rate is far below the popular mark ; 
but in considering this important question, it 

* The Constructors and Engineers of the Navy are unsurpassed 
in professional art or science, and when conjoined with naval officers — ■ 
who should always determine the warlike essentials of ships — they 
are capable of producing a steam fleet that would meet the require- 
ments of all reasonable conditions. And we venture to say, that the 
failures with which they have been charged, would be found on inves- 
tigation to be solely attributable to undue extraneous influences. 



42 EATIO OF POWER TO SPEED. 

should not be forgotten, that, unlike the paddle, 
the screw will always co-operate with sail ; and 
that if a ship would go far under steam, she must 
be content to go gently. The natural law regu- 
lating the speed of a ship is, that the power 
requisite to propel her varies as the cube of the 
velocity. 

Let it be distinctly understood what power 
is here meant: as the power applied to the 
propulsion of a vessel, is only that which acts 
upon her in the direction of the keel ; and as, 
of the gross indicated power developed by her 
engine, one portion is absorbed in working the 
organs of its mechanism, another in overcoming 
the friction of the load, while still other pro- 
portions are expended in the slip of the propeller 
and in the friction of its surfaces on the water, — 
only that portion of the gross power which 
remains, is applied to propulsion; and it is this 
remainder which varies in the ratio of the cube 
of the speed. 

Hence a steamer, that with 500 horse-power 
can make eight knots per hour, will require rather 
more than 1000 horse-power to drive her at the 
speed of ten knots — the law being thus modified 
by the increased resistance consequent upon the 
greater weight of the large engines; and thus a 
limit to speed is imposed, depending upon the 



A GREAT DISCOVERY. 43 

weight of machinery which, relative to her dimen- 
sions, a ship can carry. A ship that at the rate 
of ten knots under steam may run 1200 miles, 
can, at the speed of eight knots, and with the 
expenditure of rather less fuel, run the distance 
of 1800 miles; and, therefore it is, many contend, 
that a man-of-war for distant service should not 
be laden with large engines, whose full power 
can rarely be wanted, and which monopolize so 
great a space and displacement, as to render it 
impossible to carry fuel for their proper develop- 
ment. 

It is true that with large power of engine, 
the vessel may command, so long as her coals last, 
the advantage of high speed, and her large cylin- 
ders will enable her, by working the steam very 
expansively, to use her fuel with great economy ; 
but there still remains the disadvantage of the 
increased first cost of the machinery, and its 
greater weight and bulk to be permanently carried, 
whether used or not, and which, by increasing the 
displacement of the vessel, proportionally dimin- 
ishes her speed. 

The last great improvement in connection 
with the screw remains to be noticed, namely, 
lining the " bushings " and " bearings " with 
" Lignum-vitse," the invention of Mr. Penn, of 
Greenwich, near London. 



44 



WOOD BEAEINGS, 




The Lignuin-vitse is introduced in the manner 
shown in the drawing. In connection therewith , 
it mnst be said that the length and diameter 
of bearings has been increased far beyond the 
proportions of former years. The " brasses " are 
bored out about three-sixteenths of an inch larger 
than the shaft ; then the recesses are slotted out 
for the reception of the y^ooden strips. If care is 
taken with this part of the operation, any number 
of strips can be supplied ready fitted ; and to put in 
a set of spare strips becomes a short and simple 
operation. 



THE NAPOLEON. 45 

Strange as it appears, these wooden bearings 
are far more durable than those of metal, and in 
some ships they have endured for years without 
any perceptible wear in those parts which had, 
previously to this invention, occasioned so much 
trouble and expense. But for this important dis- 
covery, it is thought by some of the most competent 
engineers, that they would have been compelled to 
abandon the use of the screw in heavy ships. 

The Napoleon, the type of the new steam ships 
of the line of the French Navy, is a good illus- 
tration of a first-class, full-powered steamer. 

Her dimensions are as follows : 



Length extreme, 




FEET. 

262 


ETCHES. 

6.40 


Length at load line, 


. 


234 


0.94 


Beam, .... 


. . 


53 


8.38 


Height between decks, 


... 


6 


8.72 


Height of lower port sill . 


. . 


7 


2.63 


Depth of hold, 


. . 


26 


9.34 


Deep load draft, 


. 


25 


3.00 


Immersed cross section, (sq. 


ft. 1063.48.) 






Displacement, 


(tons 5050.) 






Diameter of cylinders, 


. 


8 


2.45 


Length of stroke, 


• 


5 


3.06 


Diameter of propeller, 


(4 bladed) 


19 


0.70 


Length " 


. . . 


1 


10 


Pitch 


(mean) 


27 


11 



She has eight boilers, each having five furnaces, consum- 
ing, at full speed (12.14 knots), 143 tons of coal per day, for 
which she stows five days' supply. — Boilers and engines 
occupy eighty-two feet in the length of the ship. 



46 DEBAEKING ZOUAVES. 

The trial of this ship has established the prac- 
ticability of adapting a propeller to a ship of the 
largest class, so as to insure great speed, and con- 
stitute a most effective man-of-war for certain 
purposes, and in certain situations; but when the 
great weight of the engines is considered, and the 
large space they occupy in the vessel — thereby 
diminishing the stowage of supplies — and further, 
that after the coal is exhausted, the 90 gun ship 
has but the sail of a 60 gun ship to rely upon, it 
is not easy to avoid the conclusion that however 
useful such a vessel may be for short passages,* 
and in those seas in which her supplies of coal 
and provisions may be constantly replenished, her 
sphere of action must be very limited, and she 
could not be relied upon for the long cruises and 
various services on which an ordinary line-of-battle 
ship is employed. 

A ship constructed on the plan of the Napo- 
leon, for the sake of gaining a speed of 12 knots 
per hour for the distance of about 2200 miles, is 
compelled to sacrifice a great part of her efficiency 
in several most important particulars. 

In time of war at short distances from port, for 
the defence of bays or harbors, or the Florida 
channel, for the speedy transport of troops to an 

* For debarking a regiment or two of Zouaves on the shores of 
the Adriatic, or upon the coast of Ireland. 



AUXILIAKY STEAM EES. 47 

adjacent coast, or to force a blockade, such a ves- 
sel would undoubtedly be a most valuable addition 
to our navy ; but her employment must necessarily 
be confined to such circumstances and such situa- 
tions; for should she unluckily fall in with an 
enemy's squadron with her coal expended, or her 
machinery rendered useless by any of the numer- 
ous accidents to which steam machinery is so con- 
stantly exposed, with her comparatively light rig, 
and want of stability in consequence of losing so 
great a weight of coals, she would hardly prove 
a very formidable opponent. 

Therefore, while admitting the importance and 
necessity of providing for special service a small 
class of fast, full-power steamers, it is submitted 
that the auxiliary screw steamer is the description 
of ship to which the largest and best consideration 
should be devoted; for to the nation possessing 
the most efficient fleet of such vessels, must belong 
the dominion of the sea. And while their cost is 
counted, let it at the same time be remembered, 
that their value can only be estimated by the char- 
acter of the service they may render, and that 
their capacity of aggression abroad, makes them 
the best defence at home. 



48 ADVANTAGE OF SPEED. 



Having briefly referred to the various views 
entertained in regard to the steam-power with 
which the navy should be furnished, it will be 
seen that a difference of opinion on this important 
subject may most reasonably be entertained. 

None can doubt the advantages of celerity 
to a man-of-war, yet many believe , it would be too 
dearly purchased by the sacrifice of space to such 
an extent as would require supplies to be often 
replenished ; as this necessity would in war confine 
the operations of the navy to our own shores. 

On the other hand, it is admitted that, without 
high speed a ship of war cannot exercise many 
of her most important functions, that she can 
neither choose an engagement, protect a convoy, 
nor enforce a blockade. 

The best exjoerience affirms the policy of giving 
to our cruisers as large steam-power as is consist- 
ent with a due development of all other warlike 
qualities ; for what would avail the superior 
armament of a ship, if the option of fighting or 
flying remain with her adversary, which must 
be the case when the latter commands higher 
speed. The introduction of improved ordnance, 
throwing heavy shells with great precision, at long 
ranges, gives increased importance to celerity; for 
in any future fleet-fight, victory should belong to 



ARTIFICIAL DRAFT. 49 

that flag having at command a steam squadron 
of superior speed, which may thereby be concen- 
trated upon any point without having been long 
under fire. 

May not the command of a maximum speed 
of 13 knots be obtained from the machinery 
now employed for a maximum speed of 10 knots ? 
It evidently may, and with great economy too, by 
the simple introduction of artificial draft, and the 
use of steam of higher pressure, when requiring 
the highest speed. 

At present, in our men-of-war, the boilers are 
proportioned for natural draft, burning about 12 
lbs. of coal per square foot of grate per hour, and 
for a steam pressure of 15 lbs. per square inch. 
If then the boilers be proportioned to burn at the 
maximum, with blowers, say 22 lbs. of coal to the 
square foot of grate, and to generate steam of 40 
lbs. to the square inch, we shall double the power 
developed by the machinery, and consequently 
derive from it the same speed that could he 
attained without blowers from double the ma- 
chinery : while the natural draft, and the usual 
pressure of 15 lbs. would give sufficient speed 
for ordinary service. The inconvenience of the 
higher pressure with blowers, could well be en- 
dured for the short and occasional period during 
which they would be required. 



50 SUGGESTIONS. 

To create a perfect Screw Frigate, a ship with 
sail power complete, and efficient for any service 
that may be required, the endeavor should be 
made — by getting rid of every dispensable article 
of weight or bulk, and without reducing supplies 
below three months' provisions and six weeks' 
water — to find space and displacement for an 
engine of sufficient force to drive her thirteen 
knots an hour, together with at least ten days' 
full consumption of fuel ; and this, it is believed, 
might be successfully accomplished in ships of 
the dimensions of the Wabash, beginning with 
a judicious reduction of spare spars, spare sails, 
and spare gear, and by the addition of blowers to 
their present machinery; a subject which should 
immediately receive the earnest consideration of 
a commission of the most intelligent officers. 

Having fixed upon the proportions of hull 
and spars, the form of propeller, and the plan 
of engine, a cautious discrimination should be 
exercised in multiplying the types of either; 
for, besides economy, many other advantages 
would flow from a wholesome restriction in this 
particular ; as it would permit us to relieve 
our ships of many of the spare spars with which 
they are encumbered, and we should probably 
not again hear of suspending the operations of 
a frigate thousands of miles away, until a crank 



CONCLUSION. . 51 

or rod could be sent to her; because when ships 
of the same class are cruising together, by a care- 
ful distribution of spare spars and machinery 
among them, it is hardly probable that damage 
would be sustained, or loss of spars or "break 
down " occur, which might not be remedied by the 
resources of the squadron. 

On the other hand, this system must not be 
carried to a Chinese extreme, lest we follow too 
long a false direction — thus losing the advantage 
of improvements constantly being made. For such 
is the change in all things pertaining to maritime 
war, that neither model of hull, plan of engine, nor 
mould of ordnance is best, unless of the latest 
creation. True progress will be most judiciously 
sought, in not departing too suddenly and widely 
from the established order. 



THE END. 



